University of Zakho

College of Engineering
Civile & Environmental Engineering Department
Geology
2nd year

Rocks

Prepared: by:
Sangar Ismat Abdulrahman
Luqman Akram Zaher

Supervised:
Dr Jalal H. Younis
Ms. Chiman
Table of Contents

1. Definition of the rocks: ...............................................................................................1

2. Introduction:................................................................................................................1
3.Type of the rocks:.........................................................................................................1
4. Sedimentary Rocks: ....................................................................................................2
5.Metamorphic Rocks:....................................................................................................2
6. Igneous Rocks:.............................................................................................................2
7. Rock on the ground and in the water: ......................................................................3
8.Volcanic rocks: .............................................................................................................3
9. The strongest and the weakest rocks: .......................................................................4
9.1 The strongest rocks:............................................................................................. 4
9.2 The weakest rocks: ............................................................................................... 4
10.Conclusion: .................................................................................................................5
11. Reference: ..................................................................................................................6

List of Figure

Figure 1: Types of Rocks ............................................................................................... 1

Figure 2: The Rock Cycle .............................................................................................. 2
Figure 3: Rock on the ground and in the water .......................................................... 3
Figure 4: Volcanic Rock ................................................................................................ 4
Figure 5: Diamond and Diabase ................................................................................... 4
Figure 6: Sedimentary Rocks........................................................................................ 4
1. Definition of the rocks:
Rocks are aggregates of different mineral grains and can be dividedinto three major
families or rock groupings. First are the Igneous (or "fire-formed") Rocks, usually
created by outpourings from various volcanoes or by cooling deep under the crust.

2. Introduction:
rock, in geology, naturally occurring and coherent aggregate of one or more
minerals. Such aggregates constitute the basic unit of which the solid Earth is
composed and typically form recognizable and mappable volumes. Rocks are
commonly divided into three major classes according to the processes thatresulted
in their formation. These classes are (1) igneous rocks,which have solidified from
molten material called magma; (2) sedimentary rocks, those consisting of
fragments derived from preexisting rocks or of materials precipitated from
solutions; and (3) metamorphic rocks, which have been derived from either
igneous or sedimentary rocks under conditions that caused changes in
mineralogical composition, texture, and internal structure. These three classes, in
turn, are subdivided into numerous groups and types on the basis of various factors,
the most important of which are chemical, mineralogical, and textural attributes.

3.Type of the rocks:

There are three main types of rocks: sedimentary, igneous, and metamorphic. Each
of these rocks are formed by physical changes—such as melting, cooling, eroding,
compacting, or deforming—that are part of the rock cycle.

Figure 1: Types of Rocks

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4. Sedimentary Rocks:
Sedimentary rocks are formed from pieces of other existing rock ororganic material.
There are three different types of sedimentary rocks: clastic, organic (biological),
and chemical. Clastic sedimentary rocks, like sandstone, form from clasts, or pieces
of other rock. Organic sedimentary rocks, like coal, form from hard, biological
materials like plants, shells, and bones that are compressed into rock.

5.Metamorphic Rocks:
Metamorphic rocks are rocks that have been changed from theiroriginal form by
immense heat or pressure. Metamorphic.
rocks have two classes: foliated and nonfoliate. When a rock with flat or elongated
minerals is put under immense pressure, the minerals line up in layers, creating
foliation. Foliation is the aligningof elongated or platy minerals, like hornblende or
mica, perpendicular to the direction of pressure that is applied. An example of this
transformation can be seen with granite, an igneous rock. Granite contains long and
platy minerals that are not initially aligned, but when enough pressure is added,
those minerals shift to all point in the same direction while getting squeezed into flat
sheets. When granite undergoes this process, like at a tectonic plateboundary, it turns
into gneiss (pronounced “nice”).

6. Igneous Rocks:
Igneous rocks (derived from the Latin word for fire) are formed when molten hot
material cools and solidifies. Igneous rocks can also be made a couple of different
ways. When they are formed inside of the earth, they are called intrusive, or
plutonic, igneous rocks. If they are formed outside or on top of Earth’s crust, they
arecalled extrusive, or volcanic, igneous rocks.

Figure 2: The Rock Cycle

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7. Rock on the ground and in the water:
Most of the rocks exposed at the surface of Earth are sedimentary-- formed from
particles of older rocks that have been broken apart by water or wind. The gravel,
sand, and mud settle to the bottom in rivers, lakes, and oceans. These sedimentary
particles may bury living and dead animals and plants on the lake or sea bottom.
With the passage of time and the accumulation of more particles, and often with
chemical changes, the sediments at the bottom of the pile become rock. Gravel
becomes a rock called conglomerate, sand becomes sandstone, mud becomes
mudstone or shale, and the animal skeletons and plant pieces can become fossils.

Figure 3: Rock on the ground and in the water

8.Volcanic rocks:
Volcanic rocks are among the most common rock types on Earth's surface. Volcanic
rock is a rock formed from lava erupted from a volcano. In other words, it differs
from other igneous rock by being of volcanic origin. Like all rock types, the concept
of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and
metamorphic rocks and constitute an important element of some sediments and
sedimentaryrocks. For these reasons, in geology, volcanics and shallow hypabyssal
rocks are not always treated as distinct. In the context of Precambrian shield
geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks.
Volcanic rocks and sediment that form from magma erupted into the air are called
"volcaniclastics," and these are technically sedimentary rocks.

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 Figure 4: Volcanic Rock

9. The strongest and the weakest rocks:

9.1 The strongest rocks:
The strongest rock in the world is diabase, followed closely by other fine-grained
igneous rocks and quartzite. Diabase is strongest in compression, tension, and
shear stress. If mineral hardness is the determining factor of strength, then
diamond is technically the strongest rock in the world.

Figure 5: Diamond and Diabase

9.2 The weakest rocks:

Sedimentary rocks tend to be the 'weakest' of the three, as Igneous and
Metamorphic rocks both undergo extreme pressures to form.

Figure 6: Sedimentary Rocks

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10.Conclusion:
Conclusion From the above paper we concluded that Igneous rock forms from
magma that cools and solidifies in a process called crystallization. Sedimentary
rock forms from the lithification of sediment. Metamorphic rock forms from rock
that has been subjected to great pressure and heat in a process called
metamorphism. Some of the most important accumulations of metallic mineral
resources are produced by igneous and metamorphic processes.

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11. Reference:
1. Carlson, D.H, Plummer, C.C and Hammersley, L., 2008: Physical geology, earth
revealed. McGrawHill. New York, NY 100

2. Spear, F.S., 1993: Metamorphic Phase Equilibria and Pressure-Temperature-Time

Paths, mineralogical Society of America, Washington, D.C., 799 pp

3. Ehlers, G.E. and Blatt, H., 1997: Petrology, Igneous sedimentary and metamorphic.
CBS publishers and distribution.4596/1-A new delhi-11000, India.

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